Just a heads up, this answer may take me a while to fully complete.
Nidoqueen
EVs: 3 HP
Highest stat: Attack
Venonat
EVs: 1 Sp. Def
Highest stat: HP
Slacking
EVs: 3 HP
Highest stat: Attack
Shedinja
EVs: 2 HP
Highest Stat: Attack
Barboach
EVs: 1 HP
Highest stat: Speed
Metagross
EVs: 3 Defense
Highest stat: Attack
Budew
EVs: 1 Sp. Atk
Highest stat: Sp. Def
Chatot
EVs: 1 Attack
Highest stat: Speed & Sp. Atk
Yanmega
EVs: 2 Attack
Highest stat: Sp. Atk
Heat, Wash, Frost, Fan, and Mow Rotom
EVs: 1 Sp. Atk & 1 Speed
Highest stats: Defense & Sp. Def
Shaymin Sky
EVs: 3 HP
Highest stat: Speed
Mandibuzz
EVs: 2 Sp. Atk
Highest stat: HP
Tornadus (Incarnate)
EVs: 3 Attack
Highest stat: Sp. Atk
Thundurus (Incarnate)
EVs: 3 Attack
Highest stat: Sp. Atk
Landorus (Incarnate)
EVs: 3 Sp. Atk
Highest stat: Attack
Digersby
EVs: 2 Attack
Highest stat: HP
Aegislash (Blade)
EVs: 2 Defense & 1 Sp. Def
Highest stat: Attack & Sp. Atk
Barbaracle
EVs: 2 Attack
Highest stat: Defense
Clauncher
EVs: 1 Sp. Atk
Highest stat: Sp. Def
Hawlucha
EVs: 2 Attack
Highest stat: Speed
Xenreas
EVs: 3 HP
Highest stats: Attack & Sp. Atk
Yveltal
EVs: 3 HP
Highest stats: Attack & Sp. Atk
Zygarde
EVs: 3 HP
Highest stat: Defense
Mega Diancie
EVs: 1 Defense & 2 Sp. Def
Highest stats: Attack & Sp. Atk
Mega Venusaur
EVs: 2 Sp. Atk & 1 Sp. Def
Highest stat: Defense
Mega Blastoise
EVs: 3 Sp. Def
Highest stat: Defense
Mega Kangaskhan
EVs: 2 HP
Highest stat: Attack
Mega Mewtwo X
EVs: 3 Sp. Atk
Highest stat: Attack
Mega Pidgeot
EVs: 3 Speed
Highest stat: Sp. Atk
Mega Altaria
EVs: 2 Sp. Def
Highest stats: Attack, Defense, & Sp. Atk
Mega Glalie
EVs: 2 HP
Highest stats: Attack & Sp. Attack
Mega Lopunny
EVs: 2 Speed
Highest stat: Attack
Mega Audino
EVs: 2 HP
Highest stats: Defens & Sp. Def
NOTE: This is going off of base stats, not minimum or maximum stats.
Hope this helps!
Sources:
I've got 721 of them.
